This fixes (tested) bug 978127. The server was actually returning a 401
not a 403. As such, the fix here was insufficient. This will now take
either of those 2 error codes. I've also tested it by changing the clock
in the cloud-init upstart job with a stanza like below, and verifying
that we do see the problem and then it resolve itself:
pre-start script
offset="10 minutes ago"
past=$(date -R --date "$offset")
date --set "$past" &&
echo ===== "set date to $past [$offset]" ===== ||
echo ===== "failed to set date to $past [$offset]" ====
end script